Liberation of Slaves By jaront Mar 31, 1619 First 20 slaves imported to Jamestown, Virginia Mar 31, 1636 Commercial Slave Trade Begins Mar 31, 1641 Massachusetts legalizes slavery. Mar 31, 1650 Connecticut legalizes slavery Mar 31, 1715 All colonies allowed Slavery Mar 31, 1738 Spainish in Florida promise freedom to runaway slaves Mar 31, 1777 Vermont is the first colony to abolish slavery Mar 31, 1808 Slave trade becomes illegal Mar 31, 1863 Emancipation Proclamation is signed